Shift the flour and baking powder and set aside.
Zest the orange and peel it, cut into chunks and puree it in a food processor.
In a large bowl, whisk eggs and sugar until light and pale and mix the pureed orange. Fold in the flour and then mix the melted butter and orange liquer.
Pour a well greased bundt pan and bake it in a preheated oven of 180"C for about 30 minutes. or until the skewers come out clean. Let it cool down and remove it carefully.
To make the Orange glaze.
Mix 1 cup confectionary sugar with 1 tablespoon of fresh orange juice and zest. Drizzle on a slightly cool cake.